Clinical Hospital, Federal University of Paraná, Curitiba, Brazil.
Am J Infect Control. 2010 May;38(4):308-14. doi: 10.1016/j.ajic.2009.09.012. Epub 2010 Jan 31.
In the last few years, carbapenem-resistant Acinetobacter baumannii isolates (CR-AB) have been identified worldwide. The first description of OXA-23-producing A baumannii in Brazil was from the city of Curitiba in 2003. The aim of the present study was to evaluate the persistence and dissemination of the first OXA-23-producing A baumannii clone isolated from patients in Hospital de Clinicas, Curitiba, Brazil.
An antimicrobial susceptibility profile of the isolates was determined by the standard agar dilution method. Molecular detection of beta-lactamase genes was done by polymerase chain reaction. The clonal relationship of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Epidemiologic and clinical features were evaluated as well.
Genotypic analysis of 172 CR-AB isolates by PFGE identified 3 distinct major PFGE clusters (A, B, and C, accounting for 36, 69, and 65 isolates, respectively). All isolates carried the bla(OXA-23)-like gene and were multidrug-resistant, but were susceptible to tigecycline and polymixin B. The mortality rate related to CR-AB infection was 45.4%, and ventilator-associated pneumonia and bloodstream infections were the most frequent clinical manifestations.
The presence of 3 clones among the CR-AB isolates suggests that cross-transmission was the main mechanism responsible for dissemination of OXA-23 producers. PFGE pattern A was genotypically similar to that of the first OXA-23-producing A baumannii clone identified in Curitiba in 1999. This clone persisted in the same hospital until April 2004. The presence of the bla(OXA-)23-like gene was the main mechanism associated with carbapenem resistance among the isolates studied.
在过去的几年中，已经在世界范围内发现了耐碳青霉烯鲍曼不动杆菌（CR-AB）的分离株。巴西库里蒂巴市于 2003 年首次描述了产 OXA-23 的鲍曼不动杆菌。本研究旨在评估从巴西库里蒂巴医院患者中分离的第一株产 OXA-23 的鲍曼不动杆菌克隆的持续存在和传播。
采用琼脂稀释法测定分离株的抗菌药物敏感性谱。通过聚合酶链反应检测β-内酰胺酶基因的分子检测。通过脉冲场凝胶电泳（PFGE）分析分离株的克隆关系。还评估了流行病学和临床特征。
通过 PFGE 对 172 株 CR-AB 分离株进行基因分析，确定了 3 个不同的主要 PFGE 簇（A、B 和 C，分别占 36、69 和 65 株）。所有分离株均携带 bla（OXA-23）样基因，对多药耐药，但对替加环素和多粘菌素 B 敏感。与 CR-AB 感染相关的死亡率为 45.4%，呼吸机相关性肺炎和血流感染是最常见的临床表现。
CR-AB 分离株中存在 3 个克隆，表明交叉传播是 OXA-23 产生菌传播的主要机制。PFGE 模式 A 在基因上与 1999 年在库里蒂巴首次鉴定的产 OXA-23 的鲍曼不动杆菌克隆相似。该克隆在同一医院一直持续到 2004 年 4 月。bla（OXA-）23 样基因的存在是研究中分离株耐碳青霉烯的主要机制。
